Ground comm is required to inform other traffic on the airfield of movement which might affect them. You don't have the big picture. I personally believe that just like big airfields where there are self-controlled movement areas (like ramps) that if moving in one of those areas at an uncontrolled field that it might not be necessary. Your example of moving a 100' from a parking space to a self-service fuel pump on an empty ramp is one instance. But if I were to have to get on any taxiway, cross any taxiway, or taxi to a location that I didn't have direct line of sight with; then I'm making a call. In addition, it is not always the call that can jam up the freq rather than the lack of pre-determined, concise communications to begin with and not some rambling commentary.

USMCFLYR